/Engine/Plugins/Animation/RigLogic/Source/RigLogicLib/Public/dna/layers/GeometryReader.h
deltaIndex must be less than the value returned by getBlendShapeTargetDeltaCount.
[Delta](API\Plugins\RigLogicLib\dna\layers\Delta) getBlendShapeTargetDelta ( std::uint16_t meshIndex, std::uint16_t blendShapeTargetIndex, std::uint32_t deltaIndex ) const